Combination process for the conversion of hydrocarbonaceous black oil

ABSTRACT

Maximum conversion of black oil charge stocks to distillable hydrocarbon products is achieved through a combination process involving solvent deasphalting, solvent deresining and multiplestage hydrocracking.

United States Patent [1 1 Watkins Nov. 27, 1973 COMBINATION PROCESS FORTHE CONVERSION OF HYDROCARBONACEOUS BLACK OIL [75] Inventor: Charles H.Watkins, Arlington I-lgts., Ill.

[73] Assignee: Universal Oil Products Company, Des Piaines, Ill.

Deasph a/rer\ Charge Stoc/r So/ven/ 8 [56] References Cited UNITEDSTATES PATENTS 2,002,004 5/1935 Gard 208/14 2,606,141 8/1952 Meyer....208/211 2,914,457 11/1959 Beavon 208/79 2,973,313 2/1961 Pevere et a1.208/211 3,227,645 1/1966 Frumkin et a1. 208/86 Primary Examinerl-lerbertLevine Attorney-J. R. Hoatson, Jr.

[57] ABSTRACT Maximum conversion of black oil charge stocks todistillable hydrocarbon products is achieved through a combinationprocess involving solvent deasphalting, solvent deresining andmultiple-stage hydrocracking.

8 Claims, 1 Drawing Figure L o Pram/cf 7'0 Recovery 1 Asp/1 alt/c IPile/7 5 Heavyfiesms COMBINATION PROCESS FOR THE CONVERSION OFHYDROCARBONACEOUS BLACK OIL APPLICABILITY OF INVENTION The inventiondescribed herein is adaptable to a process for the conversion ofsulfurous, heavy carbonaceous material into lower-boiling hydrocarbonproducts of reduced sulfur concentration. More specifically, the presentinvention is directed toward processing asphaltene-containingcontaminated charge stocks sometimes referred to in the art as blackoils. In particular, the process encompassed by my invention affords themaximum production of desulfurized, distillable hydrocarbons from blackoil charge stocks.

Petroleum crude oils, particularly the heavy oils extracted from tarsands, topped or reduced crudes, vacuum residuum, etc., contain highmolecular weight sulfurous compounds in exceedingly large quantities. Inaddition, black oils contain excessive quantities of nitrogenouscompounds, high molecular weight organometallic complexes, principallycontaining nickel and vanadium, and varying quantities of asphaltenicmaterial. An abundant supply of these hydrocarbonaceous charge stocksexists, most of which have a gravity less than about 20.0 API. Blackoils are generally further characterized by a boiling range indicatingthat 10.0 percent by volume, or more, boils above a temperature of about1,050F.

Knowledgeable experts in the various appropriate areas are currentlytheorizing that a severe energy crisis is soon to be encounterred. Forexample, those possessing expertise in oil and gas exploration predictthat the supply of natural gas, compared to an ever-increasing demand,will soon reach critical low proportions. Several processes are,therefore, presently being proposed which will convert naphtha, viasteam reforming and shift methanation, to a methane-rich substitutenatural gas. This, in turn, will result in a naphtha shortage for motorfuel production, especially in view of the need to produce voluminousquantities of lead-free gasolines in order to aleviate severeatmospheric pollution. Kerosine fractions, normally utilized as jet fuelfor aircraft, will. be necessarily converted to naphtha fractions andmotor fuels. Inshort, new technology is required to insure and affordvirtually 100.0 percent utilization of petroleum crude oils and theheavy distillates derived therefrom. In the petroleum refining art, thisis often referred to as utilization of the bottom of the barrel. The useof the foregoing described high molecular weight black oils, as thesource of more valuable liquid hydrocarbon products, is virtuallyprecluded by present-day refining techniques, especially in view of thehigh metals and asphaltene content.

The combination process of the present invention is particularlydirected toward the catalytic conversion of black oils to producedesulfurized, distillable hydrocarbons, and to effect such conversion ina manner which results in a volumetric yield approaching and/orexceeding 100.0 percent. Specific examples of black oils, illustrativeof those to which the present process is applicable, include a vacuumtower bottoms having a gravity of 7.1 API, and containing 4.05 percentby weight of sulfur and 23.7 percent by weight of asphaltics; a toppedcrude oil, having a gravity of 11.0 API, and containing 10.1 percent byweight of asphaltics and 5.20 percent by weight of sulfur; and, a vacuumresiduum having a gravity of about 8.8 API, containing 3.0 percent byweight of sulfur and 4,300 ppm. by weight of nitrogen, and having a 20.0volumetric distillation temperature of about 1,055F.

OBJECTS AND EMBODIMENTS An object of the present invention is to providean economically feasible fixed-bed catalytic process for convertinghydrocarbonaceous black oils into distillable hydrocarbons of lowermolecular weight and boiling range. A corollary objective is to maximizethe production of desulfurized hydrocarbons from a given quantity of anasphaltene-containing black oil.

Another object is to provide a process which affords an extension of theeffective, acceptable life of the catalytic composite employed in theconversion reaction zones.

Therefore, the present invention encompasses a process for theconversion of an asphaltene-containing hydrocarbonaceous charge stock,to produce lowerboiling hydrocarbon products, which process comprisesthe steps of: (a) deasphalting said charge stock with a selectivesolvent, in a first solvent extraction zone, at extraction conditionsselected to provide (i) a solvent-lean asphaltic pitch and (ii) asolvent-rich, deasphalted first liquid phase; (b) deresining at least aportion of said first liquid phase with a selective solvent, in a secondsolvent extraction zone, at extraction conditions selected to provide(i) a solvent-lean resin concentrate and (ii) a deresined second liquidphase; (0) reacting at least a portion of said resin concentrate withhydrogen, in a first catalytic reaction zone, at hydrocrackingconditions selected to convert resins into lower-boiling hydrocarbons;(d) reacting at least a portion of said deresined second liquid phaseand at least a portion of the resulting first reaction zone effluentwith hydrogen, in a second catalytic reaction zone, at hydrocrackingconditions selected to produce lowerboiling hydrocarbon products; and,(e) recovering said lower-boiling hydrocarbon products from theresulting second reaction zone effluent.

Other embodiments of my invention reside in particular operatingconditions and techniques, catalytic composites for utilization in thefixed-bed reaction zones, preferred selective solvents, etc. Forexample, in one such other embodiment, the extraction conditions in saidsecond extraction zone include a higher temperature (10F. to 200F.higher) than that in said first extraction zone. In another embodiment,at least a portion of the resulting first reaction zone effluent isintroduced into the second solvent extraction zone.

SUMMARY OF INVENTION Heretofore, when attempting the maximum recovery ofdesulfurized distillable hydrocarbons from the conversion of heavyhydrocarbonaceous material as hereinbefore described, the principaldifficulty encountered involved declining catalyst activity andstability resulting from the lack of a suitable processing techniquepermitting severe conditions of operation required to convertnon-distillables into the lower-boiling products, while simultaneouslyeffecting an acceptable degree of hydrodesulfurization. Catalystinstability, when processing black oil charge stocks in a fixed-bedreaction system, also stems from the presence of the asphaltic material.The asphaltic material consists primarily of high molecular weight,non-distillable coke precursors, insoluble in light hydrocarbons such aspentane or heptane. Generally, the asphaltic material is dispersedwithin the black oil, and, when subjected to the operating conditionsrequired to effect desulfurization, has the tendency to agglomerate andpolymerize, as a result of which the active surfaces of the catalyticcomposite are effectively shielded from the material being processed.The metallic contaminants, associated with the high-boiling asphaltenicfraction, adversely affect catalyst stability and activity by becomingdeposited within the internal catalylically active sites.

Heretofore, when effecting the fixed-bed catalytic processing ofhydrocarbonaceous black oils, two principal approaches have beenadvanced; liquid-phase hydrogenation and vapor-phase hydrocracking. Inthe former type of process, the charge stock is passed upwardly, inadmixture with hydrogen, into a fixedfluidized catalyst bed, or slurryof subdivided catalyst. This technique is relatively ineffective sincethe asphaltics are finely dispersed within the charge stock and theprobability of effecting simultaneous contact between the catalystparticle, the hydrogen required for the prevention of coke formation andthe aspaltic molecule is remote. Additionally, the retention ofunconverted asphaltics, suspended in a free liquid-phase oil for anextended period of time, results in additional flocculation andagglomeration. Vapor-phase hydrocracking, which requires a fixed-bedcatalytic system, is precluded ue to extreme catalyst deactivation as aresult of the deposition of coke thereon and metallic contaminantstherein.

The combination process, encompassed by the pres- 'ent inventiveconcept, utilizes a solvent deasphalting, or solvent extraction zone toprecipitate and remove a metal-containing asphaltic concentrate. It mustnecessarily be acknowledged that the prior art is replete with a widespectrum of techniques for effecting solvent deasphalting ofasphaltene-containing hydrocarbonaceous charge stocks. No attempt isherein made to claim solvent deasphalting other than as an integralelement of the present combination process. Any suitable solventdeasphalting technique known in the prior art may be employed, severalexamples of which are hereinafter described. In the interest of brevity,no attempt will be made to delineate exhaustively the solventdeasphalting art.

Exemplary of such prior art is US. Pat. No. 1,948,296 (Class 208-4) inwhich a separated asphaltic fraction is admixed with a suitable oil andsubjected to oxidation to obtain a particular asphalt product. Suitablesolvents include light petroleum hydrocarbons such as naphtha,casing-head gasoline, light petroleum fractions comprising propane,n-butane and isobutane, certain alcohols, ether and mixtures thereof,etc.

US. Pat. No. 2,002,004 (Class 208-l4) involves a 2-stage deasphaltingprocess wherein the second stage completes the precipitation of asphaltswhich was only partially effected in the first stage. As notedpreviously, the described solvents include naphtha, casing headgasoline, and liquefied normally gaseous hydrocarbons such as ethane,propane, butanes, and mixtures thereof, etc.

U.S. Pat. No. 2,914,457 (Class 208-79) describes a multiple combinationprocess involving fractionation, vacuum distillation, solventdeasphalting,. hydrogenation and catalytic reforming. Again, thesuitable liquid deasphalting solvents include liquefied normally gaseoushydrocarbons such as propane, n-butane, isobutane, as well as ethane,ethylene, propylene, nbutylene, isobutylene, pentane, isopentane, andmixtures thereof.

In accordance with the present invention, the deasphalting zonefunctions to reject an asphaltic pitch and to produce a deasphalted oilcontaining convertible resins. Significantly, prior art techniques donot distinguish between the asphaltenic material and resins; that is,prior art processes reject resins along with the asphaltic pitch. Thisis contrary to the present combination process wherein theresin-containing deasphalted oil is subjected to a solvent deresiningtechnique. The solvent-lean resin concentrate is subsequently reactedwith hydrogen, in a first catalytic reaction zone at hydrocrackingconditions selected to convert resins into lower-boiling hydrocarbons.The deasphalted and deresined oil, preferably in admixture with thelowerboiling hydrocarbons from the conversion of the resin concentrate,is reacted in a second catalytic reaction zone at hydrocrackingconditions selected to produce additional lower-boiling hydrocarbons.

In the present specification and the appended claims, the terms,deasphalting and deresining, designate the separate rejection of anasphaltic pitch and a resin concentrate from the black oil charge stock.The precise nature of these two fractions is widely dependent upon theorigin of the crude oil and on the extraction conditions employed. Inpractice, deasphalting generally refers to a one-stage precipitation asapplied to an asphalt-containing residuum, whereas deresining refers toa similar treatment conducted on an essentially asphalt-free residuum.Accordingly, deasphalting and deresining apply to the rejection of twocontiguous bottoms fractions regardless of their exact nature.

Deasphalting and deresining are carried out under the same general rangeof operating conditions. However, a preferred technique involvesoperating the deresining zone at a higher temperature than thedeasphalting zone, about 10F. to about 200F. higher, in order to recoverthe resin concentrate with the deasphalted oil, while rejecting anasphaltic pitch. The solvent extraction zones will function attemperatures in the range of about 50F. to about 600F., and preferablyfrom about F. to about 400F.; the pressure will be maintained within therange of about 100 to about 1,000 psig., and preferably from about 200to about 600 psig. The solvent/oil volumetric ratio will generally be inthe range of about 2.0:1.0 to about 30011.0. In accordance with thepresent invention, the deresining operation will employ a highertemperature and a greater solvent/oil volumetric ratio. For example, inthe situation where propane is employed as the selective solvent,deasphalting will be effected at a solvent/oil ratio of 6.0210 and atemperature of 100F. to F.; the deresining zone will utilize apropane/oil ratio of l0.0:1.0 and a temperature of 140F. to about 180F.

The rejected asphaltic pitch has an average molecular weight in therange of 3,000 to 6,000, and will contain 75.8 percent to 90.0 percentby weight of the metallic contaminants originally present in the freshfeed charge stock. The sulfur content will be approximately twice thatof the charge stock. The resin concentrate will exhibit a significantlylower average molecular weight, about 1,000 to about 4,000, and willcontain a minor proportion of metals; the sulfur content will be aboutone and one-half times that of the charge stock. The precise operatingconditions in the solvent extraction zones will generally depend uponthe physical characteristics of the feed stock as well as the selectedsolvent.

Judicious operating procedure involves the selection of temperature andpressure to maintain the extraction operations in liquid phase. Suitablesolvents include those hereinbefore described with respect to prior artdeasphalting techniques. Thus, it is contemplated that the, solvent willbe selected from the group of light hydrocarbons including ethane,methane, propane, butane, isobutane, pentane, isopentane, neopentane,hexane, isohexane, heptane, the mono-olefinic counterparts thereof, etc.Furthermore, the solvent may be a normally liquid naphtha fractioncontaining hydrocarbons having from about five to about 14 carbon atomsper molecule, and preferably a naphtha distillate having an end boilingpoint below about 200F. The solvent-rich, normally liquid phase isintroduced into a suitable solvent recovery system, the design andoperation of which are thoroughly described in the prior art.

In accordance with the present combination process, therefore, theconvertible resin concentrate is processed in a separate reaction zoneat conditions selected to convert the sameinto lower-boilinghydrocarbons. The scheme additionally permits the processing of thedeasphalted and deresined oil in the absence of both asphalts and resinsand under conditions reflecting greater yields of normally liquidhydrocarbon products. A preferred operating techique involvesintroducing at least a portion of the converted resin concentrateeffluent into the deresining zone for the recovery therein of thelower-boiling products along with the normally liquid deasphalted oil.The mixture is then separately processed in a second hydrocrackingand/or hydrotreating reaction zone.

Although the catalytic composites, disposed within the first and secondreaction zones, may be of different physical and chemicalcharacteristics in many instances, suchis not an essential feature of myinvention, and the catalytic composites may, therefore, be identical.Regardless, the catalytic composites utilized in the present combinationprocess comprise metallic components selected from the metals of GroupsVl-B and VIII of the Periodic Table, as well as compounds thereof. Thus,in accordance with the Periodic Table of the Elements, E. H. Sargent andCompany, 1964, suitable metallic components are those selected from thegroup consisting of chromium, molybdenum, tungsten, iron, ruthenium,osmium, cobalt, rhodium, iridium, nickel, palladium, and platinum.Additionally, recent investigations have indicated that catalyticcomposites, especially for utilization in the conversion of exceedinglyhigh sulfur content feed stocks, are improved through the incorporationof a zinc, tin and/or bismuth component. The latter three metalliccomponents are more advantageously utilized, in the present invention,as part of the catalytic composite selected to process the resinconcentrate.

in the present specification and the appended claims, the utilization ofthe term component," when referring to the catalytically active metal,or metals, is intended to encompass the existence of the metal as acompound, such as oxide, sulfide, etc., or in the elemental state.Regardless, the concentrations of metallic components are calculated asif the metal existed within the composite in theelemental state. Whileneither the precise composition, nor the method of manufacturing thevarious catalytic composites, is considered essential to my invention,certain aspects are preferred. For example, since the charge stock tothe present process is generally of a high-boiling nature, it ispreferred that the catalytically active metallic components possess thepropensity for effecting hydrocracking reactions while simultaneouslypromoting the conversion of sulfurous compounds into hydrogen sulfideand hydrocarbons. The concentration of the active metallic component, orcomponents, is primarily depended upon the particular metal as well asthe physical and/or chemical characteristics of the charge stocks. Forexample, the metallic components of Group Vl-B are generally present inan amount within the range of about 4.0 percent to about 30.0 percent byweight, the iron-group metals in an amount within the range of about 0.2percent to about 10.0 percent by weight, whereas the noble metals ofGroup VIII are preferably present in an amount within the range of about0.1 percent to about 5.0 percent by weight. In those instances where azinc, tin and/or bismuth component is employed, the same will generallybe present in an amount within the range of about 0.01 percent to about2.0 percent by weight. All concentrations are computed as if themetallic components existed within the catalytic composite in theelemental state.

The porous carrier material, with which the catalytically activemetallic component, or components are combined, comprises a refractoryinorganic oxide of the character thoroughly described in the literature.When of the amorphous type, alumina, or alumina in combination withabout 10.0 percent to about 10.0 percent to about 90.0 percent by weightof silica is preferred. When processing heavier charge stocks containinga significant quantity of hydrocarbons having normal boiling pointsabove a temperature of about 950F., and particularly the resinconcentrate, it may be appropriate to utilize a carrier materialcomprising a crystalline aluminosilicate, or zeolitic molecular sieve.In many instances, such a carrier material will;b e utilized inprocessing the deasphalted oil admixture with the resin concentrateeffluent. Suitable zeolitic material includes mordenite, faujasite, TypeA or Type U molecular sieves, etc., and these may be employed in asubstantially pure state; however, it is understood that the zeoliticmaterial may be included within an amorphous matrix such as silica,alumina, and mixtures of alumina and silica. it is further contemplatedthat the catalytic composites may have incorporated therein a halogencomponent, such component being selected from the group consisting offluorine, chlorine, iodine, bromine, and mixtures thereof. The halogen,component will be composited with the carrier materialin such a manneras-results in a final catalytic composite containing from about 0.1percent to about 2.0 percent by weight, again calculated as the element.

A particularly preferred catalytic composite, for utilization in thefirst reaction zone processing the resin concentrate, is that describedin U. S. Pat. No. 3,640,817 (Class 208 -59). Briefly, this catalyticcomposite is described as having more than 50.0 percent of the macroporevolume characterized by pores having pore diameters greater than about1,000 Angstroms. This catalytic composite will contain, in addition toalumina and silica, boron phosphate in theamount of about 5.0 percent toabout 30.0 percent by weight.

The metallic components may be incorporated within the catalyticcomposite in any suitable manner including co-precipitation orcogellation with the carrier material, ion-exchange or impregnation ofthe carrier material, or during a co-extrusion procedure. Following theincorporation of the metallic components, the catalytic composite isdried and subjected to a high temperature calcination or oxidationtechnique at a temperature of about 750F. to about 1,300F. When acrystalline aluminosilicate is utilized within the carrier material, theupper limit for the calcination technique is preferably about 1,000F.

With respect to the operating conditions imposed upon the catalyticreaction zones, they are selected primarily to effect the conversion ofsulfurous compounds to hydrogen sulfide and hydrocarbons. The secondreaction zone will generally function at operating conditions providinga greater severity of operation, although such technique is notnecessarily essential. The variance in operating severity between thetwo reaction zones may be obtained by the adjustment of the pressure,maximum catalyst bed temperature and liquid hourly space velocities. Thehigher severity operation within the second reaction zone will normallybe effected at an increased pressure, an increased maximum catalyst bedtemperature and at a somewhat decreased liquid hourly space velocity, orsome combination thereof.

With the exceptions as above noted, suitable ranges for the variousoperating variables will generally be the same for both reactionsystems. Thus, the pressure will generally be within the range of about200 to about 3,000 psig., the hydrogen concentration will be about 500to about 30,000 scf./Bbl., the maximum catalyst bed temperature willrange from about 600F. to about 900F. and the liquid hourly spacevelocity will vary from about 0.25 to about 2.50. In view of the factthat the reactions being effected within both reaction zones areprincipally exothermic in nature, an increasing temperature gradientwill be experienced as the reactants traverse the catalyst bed.Preferred operating techniques dictate that the increased temperaturegradient be limited to a maximum of about 100F., and, in order tocontrol the temperature gradient, it is within the scope of the presentinvention to employ quench streams, either normally liquid, or normallygaseous, introduced at one or more intermediate loci of the catalystbed.

Other conditions and preferred operating techniques will be given inconjunction with the following description of the present process. Infurther describing this combination process, reference will be made tothe accompanying drawing which illustrates one specific embodiment. Inthe drawing, the embodiment is presented by way of a simplified flowdiagram in which such details as compressors, pumps, heaters andcoolers, instrumentation and controls, heat-exchange and heatrecoverycircuits, valving, start-up lines and similar hardware have been omittedas being non-essential to an understanding of the techniques involved.The use of such miscellaneous appurtenances, to modify the process, iswell within the purview of one skilled in the art, and the use thereofwill not remove the resulting process from the scope and spirit of theappended claims.

For the purpose of demonstrating the illustrated embodiment, the drawingwill be described in connection with the conversion of a vacuum bottomscharge stock in a commerciallyscaled unit. It is understood that thecharge stock, stream compositions, operating conditions, design offractionators, separators and the like are exemplary only, and may bevaried widely without departure from the spirit of my invention.

DESCRIPTION OF DRAWING With reference now to the drawing, theillustrated embodiment will be described in conjunction with acommerciallyscaled unit designed to produce a maximum quantity ofsubstantially desulfurized, distillable hydrocarbon products from thevacuum bottoms which has a gravity of about l0.l API. Other pertinentproperties of the vacuum bottoms charge stock include a sulfurconcentration of 3.08 percent by weight, 3,300 ppm. of nitrogen, l86ppm. by weight of nickel and vanadium and 5.2 percent by weight ofheptane-insoluble asphaltic material.

The vacuum bottoms charge stock, in an amount of about 100,000 Bbl./day,is introduced, via line 1, into deasphalter 2, wherein itcountercurrently contacts a pentane solvent being introduced via line 3.The solvent to charge stock volumetric ratio is 3.0 and a liquid-phaseoperation is maintained in deasphalter 2 at a temperature of 295F. and apressure of 400 psig. An asphaltic pitch, in an amount of about 14.92percent by weight is withdrawn as a solvent-lean phase in line 4, whilea deasphalted oil, containing a resin concentrate, is removed via line5. The deasphalted oil, having a gravity of about 13.3 API, andcontaining 50.0 ppm. by weight of metals, is introduced into deresinator7 in admixture with a resin concentrate effluent from line 6, the sourceof which is hereinafter described. Additional pentane solvent, added togive a volumetric ratio to the deasphalted oil of 6.0, is introduced vialine 8, and the deresinator is maintained at a temperature of 320F. anda pressure of about 400 psig.

A solvent-lean resin concentrate, in an amount of about 27,000 BbL/day,is withdrawn by way of line 9, and introduced thereby into fixed-bedreactor 10. The resin concentrate is admixed with hydrogen in an amountof about 7,500 scf./Bbl., and the mixture enters reactor 10 at atemperature of 700F. (the increasing temperature gradient is maintainedat 50F.) and a pressure of about 3,000 psig.; the liquid hourly spacevelocity, based only a fresh feed exclusive of liquid recycle, is 0.5.Reactor 10 contains a catalytic composite similar to that described inthe previously mentioned U.S. Pat. No. 3,640,817 (Class 208-59). In thepresent instance, the catalyst is a composite of 66.90 percent by weightalumina, 7.90 percent silica, 7.20 percent boron phosphate, 2.0 percentnickel and 16.0 percent by weight of molybdenum. Product yields andcomponent distribution of the resin concentrate product effluent arepresented in the following Table I:

In actual practice, that portion of the product effluent, as shown inTable I, boiling below about 650F. will be removed and recovered priorto recycling the 650F.-plus remaining portion via line 6 into deresiningzone 7. Heavy,

TABLE I: Resin Concentrate Effluent Component Wt.% Vol.% BbL/day Ammonia0. l l Hydrogen Sulfide 2.41

Methane 0.49

Ethane 0.45 Propane 0.56

9 Butanes 0.57 1.05 284 Pentanes 0.44 0.74 200 Hexanes 0.69 1.06 286Heptane-350F. 2.89 4.03 1,773 350F.550F. 9.90 12.53 3,383 550F.650F.9.18 11.03 2,978 650F.-PLUS 74.02 79.03 21,338

* Includes hydrogen consumption of 1.71%

metal-containing resins are removed, via line 11, in an amount of about7.46 percentby weight of the fresh vacuum bottoms feed. The deasphaltedoil, inclusive of the 21,338 BbL/day of the 650F.-PLUS resin concentrateeffluent is removed by way of line 12, and introduced thereby, in thetotal amount of 81,338 BbL/day into reactor 13.

Reactor 13 contains a catalytic composite of 1.9 percent by weight ofnickel and 14.0 percent by weight of molybdenum combined with anamorphous carrier material of 33.0 percent by weight of silica and 67.0percent by weight of alumina. The charge to reactor 13 has a gravity of16.9 API, a sulfur content of 2.01 percent by weight, a nitrogen contentof 2,900 ppm. and contains only 3.0 ppm. of metal contaminants. The feedis admixed with about 13,000 scf./Bbl. of hydrogen and contacts thecatalyst at a liquid hourly space velocity of 0.35. The maximum catalystbed temperature is controlled at 775F., and the pressure is maintainedat a level of 3,000 psig. That portion of the normally liquid producteffluent boiling above 700F. is recycled to reactor 13 to provide acombined liquid feed ratio of 1:11. The remainder is sent via line 14 tosuitable separation facilities for recovery of various product streams.Yields and component distribution of the effluent from reactor 13 arepresented in the following Table 11:

* Includes hydrogen comsumption of 3.01% by weight Overall volumetricyields, inclusive of butanes, based upon the 100,000 BbL/day of freshvacuum bottoms charge stock, are presented in the following Table III:

TABLE 111: Overall Volumetric Yields Component Vol.% BblJday Butanes3.25 3,253 Pentanes 2.38 2,380 Hexanes 2.76 l-leptane- Heptane-350F.15.88 15,877 350F.550F. 45.58 45,581 550F.700F. 32.44 32,439

TOTALS: 102.30 102,289 Based upon 100,000 BbL/day fresh feed It will beimmediately noted that the present combination process produces a 102.3percent volumetric yield of normally liquid hydrocarbons, based upon thequality of fresh feed charge stock, notwithstanding the by-productproduction of 14.92 percent of weight of the asphaltic pitch and 7.46percent by weight of the heavy metallic resins both of which may be usedin road asphalt. Analyses indicate that all treams are substantiallysulfur-free and that the heptane-350F. stream, having a gravity of about55.0 API, contains 7.0 percent aromatics, 60.0 percent naphthenes and33.0 percent paraffins. As will be recognized, this constitutes anexcellent feed stock for a catalytic reforming unit.

The foregoing illustrates the method of effecting the present inventionand indicates the benefits afforded through the utilization thereof.

1 claim as my invention:

1. A process for the conversion of an asphaltenecontaininghydrocarbonaceous charge stock, to produce lower-boiling hydrocarbonproducts, which process comprises the steps of:

a. deasphalting said charge stock with a sensitive solvent, in a firstsolvent extraction zone, at extraction conditions selected to provide(i) a solvent-lean asphaltic pitch and (ii) a solvent-rich, deasphaltedfirst liquid phase;

b. deresining at least a portion of said first liquid phase with aselective solvent, in a second solvent extraction zone, at extractionconditions selected to provide (i) a solvent-lean resin concentrate and(ii) a deresined second liquid phase;

c. reacting at least a portion of said resin concentrate with hydrogen,in a first catalytic reaction zone, at hydrocracking conditions selectedto convert resins into lower-boiling hydrocarbons;

d. reacting at least a portion of said deresined second liquid phase andat least a portion of the resulting first reaction zone effluent withhydrogen, in a second catalytic reaction zone, at hydrocrackingconditions selected to produce lower-boiling hydrocarbons; and,

e. recovering said lower-boiling hydrocarbon products from the resultingfirst and second reaction zone effluents.

2. The process of claim 1 further characterized in that the extractionconditions in said second extraction zone include a higher temperaturethan that in said first extraction zone.

3. The process of claim 1 further characterized in that the resultingfirst reaction zone effluent is introduced into said second solventextraction zone.

4. The process of claim 1 further characterized in that the selectivesolvents in said first and second extraction zones comprise a lighthydrocarbon containing from one to about seven carbon atoms permolecule.

5. The process of claim 1 further characterized that said selectivesolvents are normally liquid naphtha fractions containing hydrocarbonshaving from about five to about 14 carbon atoms per molecule.

6. The process of claim 5 further characterized in that said naphthafractions have end boiling points below about 200F.

7. The process of claim 11 further characterized in that thehydrocracking conditions, in said first and second reaction zones,include a pressure from about 500 to about 5,000 psig., a hydrogenconcentration in the range of about 1,000 to about 30,000 scf./Bbl., aliquid hourly space velocity of from about 0.25 to about 2.50 and amaximum catalyst bed temperature in the range of 600F. to about 900F.

8. The process of claim 11 further characterized in that said first andsecond reaction zones have disposed therein a catalytic composite of aporous carrier material, a Group VI-B metal component and a Group VIIImetal component.

2. The process of claim 1 further characterized in that the extractionconditions in said second extraction zone include a higher temperaturethan that in said first extraction zone.
 3. The process of claim 1further characterized in that the resulting first reaction zone effluentis introduced into said second solvent extraction zone.
 4. The processof claim 1 further characterized in that the selective solvents in saidfirst and second extraction zones comprise a light hydrocarboncontaining from one to about seven carbon atoms per molecule.
 5. Theprocess of claim 1 further characterized that said selective solventsare normally liquid naphtha fractions containing hydrocarbons havingfrom about five to about 14 carbon atoms per molecule.
 6. The process ofclaim 5 further characterized in that said naphtha fractions have endboiling points below about 200*F.
 7. The process of claim 1 furthercharacterized in that the hydrocracking cOnditions, in said first andsecond reaction zones, include a pressure from about 500 to about 5,000psig., a hydrogen concentration in the range of about 1,000 to about 30,000 scf./Bbl., a liquid hourly space velocity of from about 0.25 toabout 2.50 and a maximum catalyst bed temperature in the range of 600*F.to about 900*F.
 8. The process of claim 1 further characterized in thatsaid first and second reaction zones have disposed therein a catalyticcomposite of a porous carrier material, a Group VI-B metal component anda Group VIII metal component.